JP7555823B2 - Lens element - Google Patents

Description

The present invention relates to a lens element that is intended to be worn in front of a person's eye to inhibit the progression of ocular refractive abnormalities, such as myopia or hyperopia.

Myopia of the eye is characterized by the eye focusing distant objects in front of the retina. Myopia is usually corrected using concave lenses, and hyperopia is usually corrected using convex lenses.

It has been observed that some individuals, especially children, when corrected using conventional single vision optical lenses, image inaccurately when observing objects at close distances, i.e. in near vision situations. Due to this imaging defect on the part of myopic children who are corrected for distance vision, the image of the near object is also formed behind the retina, even in the foveal area.

Such imaging defects may affect the progression of myopia in such individuals. In most of the above individuals, it may be observed that the myopic defect increases over time.

Experimental realization of an imaging system with an extended depth of field, Appl. Opt. , 44(14):2792-2798, May 2005

There appears to be a need, therefore, for a lens element that inhibits or at least slows the progression of refractive errors of the eye, such as myopia or hyperopia.

To this end, the invention relates to a lens element intended to be worn in front of a wearer's eye, comprising:
a prescription portion configured to provide the wearer with a first refractive power based on the wearer's prescription that corrects the anomalous refraction of said eye of the wearer in a standard wearing situation;
a plurality of successive optical elements;
Equipped with
Each optical element is
The present invention proposes a lens element having a simultaneous bifocal optical function that simultaneously provides a second optical function in a standard wearing situation, and a third optical function of not focusing an image on the retina of the eye in said standard wearing situation, thereby slowing down the progression of anomalous refraction of the eye.

Advantageously, having multiple contiguous optical elements simultaneously providing second and third optical functions makes it possible to have an easily constructed lens element that has a portion of the optical focus on the wearer's retina and a portion of the optical focus either in front of or behind the wearer's retina, thereby slowing the progression of refractive errors of the eye, such as myopia or hyperopia.

Potentially, lens elements according to the present invention may further allow for the ability to select portions of light that should be focused on the retina and portions of light that should not be focused on the retina of the eye.

According to further embodiments, which may be considered alone or in combination,
- the refractive power of the second optical function in a normal wearing situation is equal to or less than 0.25 diopters; and/or - each optical element has an optical axis; and/or - the lens elements are edged lens elements intended to be mounted in a spectacle frame, the entire surface of at least one face of the lens element being covered with a plurality of continuous optical elements; and/or - at least a part of the prescription portion, e.g. a zone of the prescription portion around the optical centre of the lens element, does not contain any optical elements; and/or - the prescription portion is formed as a part other than the part formed as a plurality of optical elements; and/or - at least a part of the optical elements, e.g. all of them, are arranged in a predefined array, e.g. a square array or a hexagonal array, on at least one surface of the lens element; and/or - at least a part of the optical elements, e.g. all of them, are arranged along a plurality of concentric rings; and/or - at least a part of the optical elements, e.g. all of them, are arranged on the front surface of the lens element; and/or at least a portion, e.g. all, of the optical elements are arranged on the rear surface of the lens element, and/or at least a portion, e.g. all, of the optical elements are arranged between the front and rear surfaces of the lens element, and/or at least a portion, e.g. all, of the optical elements are made of a birefringent material, and/or at least a portion, e.g. all, of the optical elements are diffractive lenses, and/or at least a portion, e.g. all, of the optical elements are π-Fresnel lenses, and/or at least a portion, e.g. all, of the diffractive lenses comprise a Metasurface structure, and/or at least a portion, e.g. all, of the optical elements are multifocal binary components, and/or at least a portion, e.g. all, of the optical elements are pixelated lenses, and/or the difference between the refractive power of the second optical function and the refractive power of the third optical function is 0.5D or more, and/or the difference between the refractive power of the first optical function and the refractive power of the third optical function is 0.5D or more, and/or At least one, e.g. all, of the optical elements have a shape configured to produce a focal plane in front of the retina of the human eye, and/or - at least a portion, e.g. all, of the optical elements have an optical function including high order optical aberrations, and/or - the lens element comprises an ophthalmic lens having a prescription portion and a clip-on having a plurality of successive optical elements configured to be removably attached to the ophthalmic lens when the lens element is worn.

The invention also relates to a method for providing a lens element intended to be worn on an eye of a wearer according to the invention, said method comprising the steps of:
- providing a lens element configured to provide the wearer with a first refractive power based on the wearer's prescription that corrects the anomalous refraction of said eye of the wearer in a standard wearing situation;
- providing an optical patch comprising a plurality of continuous optical elements;
forming a lens element by placing an optical patch on one of the front or back surfaces of a lens member;
Including,
Each optical element, when the patch is disposed on one of the front or back surface of the lens member,
- a simultaneous bifocal optical function and e.g. an optical axis, which simultaneously provides a second optical function in a standard wearing situation, and - a third optical function of not focusing an image on the retina of the eye in said standard wearing situation, thereby slowing down the progression of anomalous refraction of the eye.

The invention further relates to a method for providing a lens element intended to be worn in front of an eye of a wearer according to the invention, said method comprising the steps of casting a lens element, and during the casting step, when said lens element is worn in front of said eye of a wearer:
providing an optical patch comprising a plurality of successive optical elements, each having an optical axis, and a simultaneous bifocal optical function that simultaneously provides a second optical function under normal wearing conditions, and a third optical function of not imaging onto the retina of the eye under said normal wearing conditions, thereby slowing the progression of ametropia of the eye.

Non-limiting embodiments of the present invention will now be described with reference to the accompanying drawings.

FIG. 2 is a plan view of a lens element according to the present invention. 1 is a general side view of a lens element according to the present invention; FIG. 2 illustrates an example of a lens element covered by multiple successive Fresnel type optical elements. FIG. 4 is a diagram illustrating an example of a radial profile of a first diffractive lens. FIG. 13 is a diagram illustrating an example of a radial profile of a second diffractive lens. FIG. 2 illustrates an example of a radial profile of a π-Fresnel lens. FIG. 1 illustrates the diffraction efficiency of a π Fresnel lens profile as a function of wavelength. FIG. 1 illustrates the diffraction efficiency of a π-Fresnel lens profile as a function of wavelength. FIG. 1 illustrates a binary lens embodiment of the present invention. FIG. 1 illustrates a binary lens embodiment of the present invention. FIG. 1 illustrates a binary lens embodiment of the present invention.

Elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present invention.

The present invention relates to lens elements, particularly lens elements intended to be worn in front of a person's eye.

In the remainder of the description, terms such as "top," "bottom," "horizontal," "vertical," "superior," "lower," "front," "rear," or other terms indicating relative positions may be used. These terms should be understood in the context of the wear of the lens elements.

In the context of the present invention, the term "lens element" can refer to a contact lens, an uncut optical lens, an eyeglass optical lens with edges to fit into a particular eyeglass frame, or an ophthalmic lens and an optical device configured to be positioned on the ophthalmic lens. The optical device can be located on the front or back surface of the ophthalmic lens. The optical device can be an optical patch. The optical device can be configured to be removably positioned on the ophthalmic lens, for example a clip configured to be clipped to an eyeglass frame having an ophthalmic lens.

The lens element 10 according to the present invention is configured for use on a human and is intended to be worn in front of the human's eyes.

As shown in FIG. 1a, a lens element 10 according to the present invention comprises:
a prescription part 12,
a plurality of successive optical elements 14 .

The prescription portion 12 is configured to provide a wearer in a standard wearing situation with a first optical function based on the wearer's eye prescription that corrects the anomalous refraction of the wearer's eye.

A wearing situation is to be understood as the position of the lens element relative to the wearer's eye, defined, for example, by the angle of pre-eye wear, the cornea-lens distance, the pupil-cornea distance, the center of rotation of the eye (CRE)-pupil distance, the CRE-lens distance, and the curvature angle.

The cornea-lens distance is the distance along the visual axis of the eye in the primary eye position (usually interpreted as horizontal) between the cornea and the back surface of the lens, and is, for example, equal to 12 mm.

The pupil-corneal distance is the distance along the visual axis of the eye between the pupil and the cornea, usually equal to 2 mm.

The CRE-pupillary distance is the distance along the visual axis of the eye between the center of rotation of the eye (CRE) and the cornea, and is, for example, equal to 11.5 mm.

The CRE-lens distance is the distance along the visual axis of the eye in the primary eye position (usually interpreted as horizontal) between the CRE of the eye and the back surface of the lens, and is, for example, equal to 25.5 mm.

The angle of vision when worn is the angle in the vertical plane at the intersection of the normal to the back surface of the lens in the first position with the visual axis of the eye, i.e., the intersection of the normal to the back surface of the lens in the first position with the visual axis of the eye, i.e., equal to -8°.

The curvature angle is the angle in the horizontal plane at the intersection of the normal to the back surface of the lens and the visual axis of the eye in the first eye position (usually interpreted as horizontal), e.g. equal to 0°.

An example of a standard wearing situation can be defined by a pre-eye angle of -8°, a cornea-lens distance of 12 mm, a pupil-cornea distance of 2 mm, a CRE-pupil distance of 11.5 mm, a CRE-lens distance of 25.5 mm, and a curvature angle of 0°.

The term "prescription" is to be understood as meaning a set of optical properties, for example power, astigmatism, prism light blur, determined by an ophthalmologist or optometrist, to correct the wearer's visual defects by means of a lens placed in front of the eye. For example, a prescription for a myopic eye has a value of power and a value of astigmatism with respect to the axis of distance vision.

Each optical element 14 of the plurality of successive optical elements has a simultaneous bifocal optical function and, for example, an optical axis.

The optical functions of each optical element 14 may differ from one another.

Simultaneous bifocal optical function:
- simultaneously providing a second optical function under normal wearing conditions, and - a third optical function of not focusing an image on the retina of the eye under said normal wearing conditions, thereby slowing down the progression of anomalous refraction of the eye.

The second and third optical functions differ at least in that the refractive powers they provide differ from each other. In the sense of the present invention, these two refractive powers are different if the absolute value of the difference between the two refractive powers is 0.1 D or more.

In the context of the present invention, two optical elements should be considered consecutive if there is a path linking them that allows measuring at least one refractive power different from the refractive power based on the wearer's prescription that corrects the anomalous refraction of the wearer's eye in a standard wearing situation.

Each optical element of the plurality of contiguous optical elements is transparent across the visible spectrum.

As shown in FIG. 1b, the lens element 10 according to the present invention has an object-side surface F1, which is formed, for example, as a convex curved surface facing the object side, and an eye-side surface F2, which is formed, for example, as a concave surface having a curvature different from that of the object-side surface F1.

According to an embodiment of the invention, at least a portion, e.g., all, of the continuous optical element is disposed in front of the lens element.

At least a portion, for example all, of the continuous optical element may be disposed on the back surface of the ophthalmic lens.

At least a portion, e.g., all, of the continuous optical element may be disposed between the front and back surfaces of the lens element. For example, the lens element may include zones of different refractive indices that form the continuous optical element.

According to an embodiment of the present invention, the lens element may comprise an ophthalmic lens having a refractive area and a clip-on having a plurality of continuous optical elements configured to be removably attached to the ophthalmic lens when the lens element is worn. Advantageously, when the person is in a distance environment, e.g., outdoors, the person may detach the clip-on from the ophthalmic lens and eventually replace it with a second clip-on without any of the continuous optical elements. For example, the second clip-on may have a solar tint. The person may also use the ophthalmic lens without any additional clip-on.

Continuous optical elements may be added to the lens element independently on each surface of the lens element.

At least a portion, e.g., all, of the continuous optical elements can be in a defined array, e.g., an array containing identical square or hexagonal cells or an array containing randomly arranged cells.

Advantageously, the inventors have observed that for a given density of optical elements, having at least a portion, e.g., all, of the optical elements arranged along multiple concentric rings increases the overall visual acuity of the lens element. For example, having a distance D between two adjacent concentric rings of the optical element of greater than 2.00 mm allows a larger refractive area to be achieved between these two rings of the optical element, thus providing better visual acuity.

A continuous optical element may cover a particular zone of a lens element, such as the center of the lens element or any other area.

According to an embodiment, the center of the lens element may not have an optical element. For example, a disk centered at a fitting cross and having a radius of more than 1.5 mm, e.g. more than 2 mm, and less than 5 mm may not have a continuous optical element.

Different portions of the lens element may not have continuous optical elements depending on design requirements.

According to an embodiment of the present invention, the prescription portion is formed as a portion other than the portion formed as a plurality of optical elements.

According to an embodiment of the invention, the lens element is a contact lens intended to be placed on the eye of a wearer, and the entire object surface of the lens element is covered with a plurality of continuous optical elements.

According to a preferred embodiment of the invention, the lens element is a rimmed lens element intended to be mounted in a spectacle frame, and the entire surface of at least one face of the lens element is covered with a plurality of continuous optical elements.

An example of such an embodiment is shown in FIG. 2, where the surface of the lens element is completely covered with multiple continuous Fresnel-type optical elements.

Such an embodiment allows for easier manufacturing with discontinuously diffused optical elements on the surface of the lens element.

The refractive power of the second optical function in a standard wearing situation may be 0.25 diopters or less, for example 0.1 diopters or less. According to an embodiment of the present invention, the refractive power of the second optical function may be a value equal to 0 diopters.

Thus, each optical element combined with the prescription portion can provide two refractive powers in a standard wearing situation. The refractive powers corresponding to the first and second optical functions provide refractive powers close to the prescribed refractive power, i.e., with a difference of 0.25 diopters or less.

The refractive powers corresponding to the first and third optical functions provide the refractive power to image light rays onto a site other than the retina of the eye.

The density or power of the continuous optical element may be adjusted according to the zone of the lens element. Typically, the continuous optical element is positioned at the periphery of the lens element to increase the effect of the continuous optical element in myopia control, for example, to compensate for peripheral defocus due to the peripheral shape of the retina.

According to a preferred embodiment of the present invention, for any circular zone having a radius between 2 mm and 4 mm and having a geometric center located at a distance of the optical center of the lens element equal to or greater than the radius + 5 mm, the ratio of the sum of the areas of the portions of the optical elements located within the circular zone to the area of the circular zone is between 20% and 70%.

Continuous optical elements can be fabricated using a variety of techniques, such as direct surface machining, molding, casting or injection, embossing, thin film processing, or photolithography. In accordance with the present invention, photolithography can be particularly advantageous, especially when one of the surfaces of the lens element is flat.

According to an embodiment of the invention, at least one, e.g., all, of the continuous optical elements have a shape configured to produce a focal plane in front of the retina of the human eye. In other words, such non-continuous optical elements are configured such that, if there are any section planes at which the light bundles converge, then every such section plane is located in front of the retina of the human eye.

According to the present invention, the continuous optical element has a multifocal refractive optical function.

In the sense of the present invention, the optical element is a "multifocal refractive microlens" that includes a bifocal surface, i.e. a surface with two surface powers, a trifocal surface, i.e. a surface with three surface powers, e.g. a progressive multifocal surface with continuously varying surface powers, including aspheric surfaces.

According to an embodiment of the invention, at least one, for example all, of the continuous optical elements is made of multiple materials. In particular, the refractive index of the optical element may be different from the refractive index of the material of the lens element .

According to an embodiment of the invention, at least one, for example all, of the continuous optical elements are made of a birefringent material. In other words, the optical elements are made of a material that has a refractive index that depends on the polarization and direction of propagation of the light. Birefringence may be quantified as the maximum difference between the refractive indices exhibited by the materials.

According to an embodiment of the invention, at least some, e.g. all, of the optical elements are diffractive lenses.

For example, at least a portion, e.g., all, of the optical elements are pixelated optical elements, such as pixelated lenses, in which one out of two pixels is associated with each optical function. Examples of pixelated lenses are disclosed in "Pixelated Lenses," IEEE Transactions on Optical Engineering, Vol. 13, No. 1, 2003, pp. 1171-1179, 2003.

According to an embodiment of the invention, at least one, e.g. all, of the continuous optical elements have a discontinuity, e.g. a Fresnel surface, and/or a refractive index profile having discontinuities.

Figure 3 shows an example of a first diffractive lens radial profile of a continuous optical element that can be used in the present invention.

Figure 4 shows an example of a second diffractive lens radial profile of a continuous optical element that can be used in the present invention.

A diffractive lens may be a Fresnel lens whose phase function ψ(r) has a π phase step at a nominal wavelength λ _0, as seen in Figure 5. For clarity, the name "π Fresnel lens" may be given to these structures, in contrast to monofocal Fresnel lenses, whose phase steps are multiples of 2π. The π Fresnel lens, whose phase function is displayed in Figure 5, diffracts light primarily in two diffraction orders (orders ₀ and +1) associated with diopter powers P(λ ₀ ) = 0δ and a positive one, e.g., P(λ ₀ ) = 3δ, at λ 0 = 550 nm.

The advantage of this design is that the diffractive orders dedicated to the wearer's prescription are achromatic, while the diffractive orders used to provide the third optical function of slowing myopia progression are highly chromatic.

Typical sizes of the optics are 2 mm or more and 2.5 mm or less. In practice, the inventors have observed that it is advantageous to keep the optic size less than the pupil size of the wearer's eye.

For example, the diffraction efficiency of the 0th and +1st orders is approximately 40% at the nominal wavelength λ ₀ .

To increase the efficiency of the diffraction orders that correspond to the wearer's prescription, the following can be considered:

To increase the efficiency of the 0th diffraction order, the value of λ ₀ can be reduced. Figure 6a shows the diffraction efficiency at λ ₀ = 550 nm, and Figure 6b shows the diffraction efficiency for λ ₀ = 400 nm. It can be noticed that in this case the diffraction efficiency of the 0th order is generally higher across the visible spectrum, while the efficiency of the +1st order is lower. In this case, the diopter power of the refractive phase function to which the phase jump is applied should be equal to 1.5 ^* 400/550 ≈ 1.1 δ for λ ₀ = 550 nm, instead of 1.5 δ in Figure 6a. This results in the ring of Figure 5 being widened.

Additionally or alternatively, one ring out of the two in the configuration shown in FIG. 5 can be set to zero. In this case, simultaneous bifocal function is still present due to the remaining Fresnel ring, while the ring set to zero induces a significant percentage of the 0 δ diopter power.

One may further consider applying a Fresnel structure made of two materials with two different refractive indices and different Abbe numbers in order to obtain the phase function of FIG. 5 at λ= _λ0 , to obtain a more uniform efficiency in the visible spectrum, and/or to privilege one of the two main diffraction orders relative to the other.

Other combinations with stacked Fresnel structures can also be considered.

According to an embodiment of the invention, at least one, e.g., all, of the continuous optical elements are multifocal binary components, e.g., multifocal binary lenses. The binary lenses may have a radial profile with a discontinuity height of about 1 μm.

For example, as shown in FIG. 7a, the binary structure mainly displays two diopter powers, shown as -P/2 and P/2, corresponding to the two main diffraction orders. When associated with a diffractive structure as shown in FIG. 7b, with a diopter power of P/2, the final structure, shown in FIG. 7c, has diopter powers 0δ and P. The case shown is associated with P=3δ.

Advantageously, the -1 and 1 order diffraction efficiencies are approximately 40% at the nominal wavelength, and in addition, the diffraction efficiency remains high across the entire visible spectrum, typically greater than 35%.

According to an embodiment of the present invention, at least a portion, e.g., all, of the diffractive lens has a metasurface structure, also called a metalens.

For example, the lens element may comprise an array of simultaneous bifocal metalenses of diopter powers P1, P2, where P1 is 0δ and has controlled chromatic aberration.

Typically, P1 = 0δ can be achromatic or partially achromatic, meaning it has the same focal point at each wavelength.

The chromatic aberration of P2 can be advantageously controlled, e.g. the focal length and efficiency can be made wavelength dependent.

The chromatic aberration of each metalens can vary as a function of the position of the metalens on the surface of the lens element: near vision, middle vision, or far vision.

Each metalens itself can be made from an array of subwavelength elements.

For example, the subwavelength elements can have any shape, any dimensions, such as circular, rectangular, or elliptical, and can be equidistant and aligned in the same direction or alternating with each other.

The subwavelength elements of the metalens should be made from high dielectric materials.

Each metalens can be made from a combination of "sub-metalens". For example, bifocality can be obtained as a function of wavelength by spatial multiplexing or stacking several sub-metalens.

Bifocality can be obtained as a function of polarization by spatial multiplexing or stacking several sub-metalenses.

According to an embodiment of the invention, at least one, e.g., all, of the continuous optical elements have an optical function having high-order optical aberrations. For example, the optical elements are microlenses composed of continuous surfaces defined by Zernike polynomials.

The present invention has been described above using embodiments without limiting the general concept of the present invention.

Many further modifications and variations will be apparent to those skilled in the art with reference to the exemplary embodiments described above, and the exemplary embodiments described above are provided by way of example only and are not intended to limit the scope of the invention, the scope of which is determined solely by the appended claims.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope of the invention.

10 Lens element 12 Prescription part 14 Optical element

Claims (12)

A lens element intended to be worn in front of a wearer's eye, comprising:
a prescription portion configured to provide the wearer with a first optical function based on the wearer's prescription that corrects anomalous refraction of the eye of the wearer in a standard wearing situation;
a plurality of successive diffractive optical elements, at least some of said plurality of successive diffractive optical elements being π-Fresnel lenses ;
Equipped with
Each optical element is
a second optical function of 0.25 diopters or less in standard wearing conditions; and a third optical function of not focusing an image on the retina of the eye in the standard wearing conditions, thereby slowing the progression of the anomalous refraction of the eye, the third optical function being different from the optical function of the prescription portion and differing from the second optical function by at least 0.1 diopters.
A lens element having a simultaneous bifocal optical function that simultaneously provides The lens element according to claim 1, wherein the lens element is a rimmed lens element intended to be mounted in an eyeglass frame, and the entire surface of at least one face of the lens element is covered with the plurality of continuous optical elements. The lens element of claim 2, wherein at least a portion of the optical elements are arranged along a plurality of concentric rings. The lens element according to any one of claims 1 to 3, wherein at least a portion of the optical element is disposed on the front surface of the lens element. A lens element according to any one of claims 1 to 4, wherein at least a portion of the optical element is made of a birefringent material. The lens element of claim 1, wherein at least a portion of the diffractive optical element includes a metasurface structure. A lens element according to any one of claims 1 to 6 , wherein at least some of the optical elements are multifocal binary components. A lens element according to any one of claims 1 to 7 , wherein at least some of the optical elements are pixelated lenses. A lens element according to any one of claims 1 to 8 , wherein a difference between a refractive power of the second optical function and a refractive power of the third optical function is 0.5D or more. A lens element according to any one of claims 1 to 9 , wherein a difference between a refractive power of the first optical function and a refractive power of the third optical function is 0.5D or more. A method for providing a lens element intended to be worn in front of the eye of a wearer according to any one of claims 1 to 10 , comprising the steps of:
- providing a lens element configured to provide the wearer with a first refractive power based on the wearer's prescription that corrects ametropia of the eye of the wearer under normal wearing conditions;
- providing an optical patch comprising a plurality of contiguous optical elements;
forming a lens element by disposing said optical patch on one of the front or back surfaces of said lens member;
Including,
Each optical element, when the optical patch is disposed on one of the front or back surfaces of the lens member,
- a second optical function under normal wearing conditions; and - a third optical function of not imaging onto the retina of the eye under said normal wearing conditions, thereby slowing the progression of the anomalous refraction of the eye. A method for providing a lens element intended to be worn in front of an eye of a wearer according to any one of claims 1 to 10 , comprising the steps of casting said lens element, and wherein, during said casting step, when said lens element is worn in front of said eye of said wearer:
providing an optical patch including a plurality of consecutive optical elements each having a simultaneous bifocal optical function that simultaneously provides a second optical function under normal wearing conditions, and a third optical function of not imaging onto the retina of the eye under said normal wearing conditions, thereby slowing the progression of the anomalous refraction of the eye.

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